Short answers, pulled from the story.
The London Underground opened on the 10th of January 1863, running between Paddington and Farringdon. It was the world's first underground passenger railway, carrying 38,000 passengers on its opening day and 9.5 million in its first year.
The London Underground earned the nickname the Tube from its deep-level lines, which were dug as smaller, roughly circular tunnels at a deeper level than the early cut-and-cover lines. The first such line, the City and South London Railway, used tunnels 10 feet 2 inches in diameter when it opened in 1890.
The London Underground has eleven lines and 272 stations. The system was used for 1.216 billion passenger journeys in 2024/25 and accommodates up to 5 million passenger journeys a day.
Most of the London Underground is not below ground. Despite its name, around 45 per cent of the system is underground, while much of the network in the outer parts of London runs on the surface.
Harry Beck designed the schematic London Underground map in 1931. It was voted a national design icon in 2006 and now also shows the DLR, London Overground, Thameslink, the Elizabeth line and Tramlink.
The largest single loss of life on the London Underground was at Bethnal Green station on the 3rd of March 1943, when a crush killed 173 people, including 62 children. Other major incidents include the Bank Station bombing on the 11th of January 1941, which killed 111, the Moorgate crash of 1975, which killed 43, and the King's Cross fire of 1987, which killed 31.
The London Underground accepts paper tickets, contactless Oyster cards, contactless bank cards and smartphone payments such as Apple Pay and Android Pay. The Oyster card was introduced in 2003, and in September 2014 TfL became the first public transport provider in the world to accept contactless bank cards.
The London Underground is operated by London Underground Limited, a wholly owned subsidiary of Transport for London. TfL was created in 2000, and control of the Underground transferred to it in July 2003.